Testing of a Strained Silicon Based 3-D Stress Sensor for Out-of-Plane Stress Measurements

A new 3-D stress sensor that features strain engineering is developed with the capability of extracting the six stress components in a full temperature compensation manner. This article presents the detailed testing of the out-of-plane shear and normal stress for the developed chip. The shear state is produced via applying horizontal force on a microfabricated two-point shear bridge structure, which is mounted on a chip on a printed circuit board. On the other side, a direct vertical force is utilized to induce normal stress directly at the sensing rosette. Finite element analysis is conducted for both loading cases to evaluate the level and uniformity of these stress components. The tested chip captures the out-of-plane shear and normal stress with 16% and 11% full scale, respectively.